## elica85 3 years ago the electric potential in a region of space is $V=350/\sqrt{x ^{2}+y ^{2}}$ where x and y are in meters. what is the strength of electric field at (x,y)=(2.6,2.8)m?

1. elica85

E=-dV/ds. gradient V= 350(-1/2)(x^2+y^2)^(-3/2)(2x)+350(-1/2)(x^2+y^2)^(-3/2)(2y). anything wrong so far?

2. swimermandie

That kinda how i did it but I keep getting the wrong answer. Let me know if this formula worked for you

3. elica85

my answer's not working either =/

4. TuringTest

wrong so far is that you have written the gradient as a scalar when it is a vector

5. TuringTest

$\vec E=-\nabla V=<-350x(x^2+y^2)^{-3/2},-350y(x^2+y^2)^{-3/2}>$now plug in the variables and find the magnitude of the vector

6. TuringTest

the magnitude is given by$\large |E|=\sqrt{E_x^2+E_y^2}$

7. elica85

thank you

8. TuringTest

welcome, I hope it works

9. elica85

worked!!

10. TuringTest

sweet :D

11. jinjin

If you cartesian coordiante to spherical coordiante, you will find the answer easier.

12. elica85

o yea but how? use r=sqrt(x^2+y^2) and then......? can't believe i can't remember how